This invention relates to a construction method for a continuous row of piles and an earth drill for use therefor, in which after a plurality of juxtaposed, vertical bores have been excavated in ground by means of an earth drill, water or ground hardening liquid is injected through a nozzle provided in the earth drill, as the earth drill is being withdrawn, into the vertical bores thus prepared, thereby forming a continuous row of juxtaposed piles serving as a pile wall or sheathing board for underground water.
Hitherto, many attempts, such as for instance, an ICOS method have been proposed for injecting into ground the mortar or the like which will be hardened thereafter, thereby forming an underground continuous wall. Typical of those attempts is that an earth drill having a hollow shaft is used for excavating ground to a given depth, after which motar or the like is injected through the hollow portion of the drill shaft into bores excavated in the ground, as the drill is being withdrawn, thereby forming a continuous row of piles under the ground.
However, according to such a prior art, there tends to often occur discontinuous portions or non-overlapped portion among the piles thus prepared, necessitating to inject the grout among piles or to the back thereof, when excavating the portion of ground encircled with such rows of piles. In addition, injection of grout sometimes accompanies difficulties which would lead to accidents such as water gushing. The invention contemplates to permeate a groundhardening liquid into the portion of ground surrounding bores which have been excavated by means of an earth drill following the excavation of bores, based on the principle disclosed in the invention, entitled "High Pressure Jet-Grouting Method", U.S. Pat. No. 3,802,203 possessed by the applicant.